This study employs various observation and analytical techniques including electron microprobe analysis, X-ray difraction (XRD) and ICP-MS(AES) on polymetallic nodules collected from the northwest continental margin of the South China Sea. The analyses indicate that the cores of the samples are made up of quartz, illite, albite and chlorite. This study comes to the conclusion that these nodules are dominative due to the special environment of the marginal sea which includes the geographical condition and the oceanic environmental factors.